Double skinned pipe assemblies are known. Commonly, they comprise of an inner pipe containing a first fluid and an outer pipe containing a second fluid in an annular space encircling the inner pipe. The second fluid is typically air and the annular space serves to contain any fluid leaking from a crack in a wall of the inner pipe. Such pipes typically form part of a long supply line. They are often segmented and connected by suitably designed couplings and can thus be disassembled and reassembled without issue.
In gas turbine engines, there is a need to feed fluids such as oil to various moving components within the engine. This presents a need for feed pipes from the fluid source across the engine. Such pipes will typically be joined to a surface of the body to be fed or scavenged in a manner which prevents leakage of oil outside of the body. For example, such pipes may be welded to the body. Conventionally, these feed pipes have been composed of a single walled pipe. With the advancement of engine technology, the temperature of air passing through the engine is ever increasing. In the event of a leakage of the pipe, there is increased risk of ignition of flammable fluids which has the potential to result in an engine fire. Consequently, great care must be taken in the selection, manufacture and installation of the material of a single walled pipe to minimise the risk of engine fire.
Whilst the use of a second skin is known to contain leaks, this presents difficulties in installation inside an engine. The use of segmented pipes and multiple couplings as is known for current double skinned pipe applications is undesirable. A challenge arises in installing a double skinned feed pipe in such an application.